The present invention relates to devices for filling containers in lost-foam casting systems.
The lost-foam casting technique represents an ever more widely employed foundry technique that is essentially based on the preparation of a model, generally made of polystyrene or some similar material, that exactly reproduces the characteristics of the piece to be cast. This model is inserted in a container (flask) filled with sand, which is then vibrated until the sand is distributed and compacted in such a manner as to adapt itself closely to and reproduce the exact shape of the model. Hot casting material (typically molten metal) is then poured into the space occupied by the model. The casting material dissolves the model and thus occupies the space that was previously occupied by the model in the surrounding sand. The final result is therefore the obtainment of a casting, i.e. a workpiece, that exactly reproduces the shape of the model.
The present invention comes to grips, first and foremost, with the problem of optimizing the operations that lead to the model being inserted or drowned in the sand prior to its compaction by vibration. In particular, the present invention avoids breakage or displacement of the model (typically realized in the form of a cluster of smaller individual models). Additionally, the invention also provides a filling device of the intelligent type, capable, in particular, of identifying the individual model and/or the container into which it has been inserted and thus making it possible, for example, to achieve selective specialization of the various processing operations, this to the point of treating each model/casting in accordance with a particular tailor-made process.
According to the present invention, this scope is attained by means of a container-filling device for lost-foam casting systems, including in a single operational combination:
supporting means for containers with associated vibration means to set the containers into vibration;
sand-feeding means capable of selectively feeding dosed quantities of sand into the containers; and
positioning means that can selectively be associated with the containers to position foam models into the containers; the positioning means being capable of sustaining the models both while the sand is being fed into the containers by the feeding means and while the containers containing the said models are being vibrated by the vibration means.